Opsin 5 photoreceptor in human skin sensory neurons: Putative regulators of their functionality

Summary: Abstract Body: Background：Opsins (OPNs) are the universal photosensitive proteins responsible for visual and nonvisual photoreception in animals and are G protein-coupled receptors having a seven-transmembrane a-helical structure. OPN5 is the most recently identified opsin in the human and mouse genomes, as a UV photoreceptor, and functions for various non-visual photoreceptions. OPN5 are now known as key players in many fundamental processes, such as local light-dependent circadian clock entrainment, melanogenesis, corneal wound healing and thermogenesis response. However, the expression and function of OPN5 in in human skin sensory neurons has not been reported. Objective: The aim of the present study was to evaluate OPN5 expression in human skin sensory neurons. Method：Differentiate sensory neurons according to the previously described scheme. human induced pluripotent stem cell (iPSC)-derived nociceptive sensory neurons (hSN) in Sensory Neuron Medium. Sensory neuron differentiation was assessed using RT-PCR. The mRNA and protein levels of OPN5 in human hSNs were detected by RT-PCR and western blot analysis, respectively. The expression and localization of OPN5 in hSNs were detected with the immunofluorescent staining under laser scanning confocal microscopy. Additionally, the skin transparent method to observe the expression of OPN5 in sensory neurons in human skin tissue. Results: The results of RT-PCR and western blot demonstrated that the expression of OPN5 mRNA and protein were detected in hSNs. OPN5 was expressed and localized to the cell membrane of hSNs under fluorescence microscopy and laser scanning confocal microscopy. 3D images of intracutaneous nerve fibers (ICNFs) of entire cleared skin sample were acquired by confocal microscopy, and the images were rendered to obtain 3D structures of the nerves. The nerve branches extend more toward superficial layers in skin and OPN5 protein expression in skin sensory neurons. Conclusion: OPN5 expression in normal skin sensory neurons and may sheds new light on the skin physiology. Yinghua Lan¹, Yu Wang¹, Hongguang Lu¹ 1. Department of Dermatology, Affiliated Hospital of Guizhou Medical University, Guiyang, China. Translational Studies: Cell and Molecular Biology